Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Robotic systems, such as autonomous robotic devices, that occupy a physical environment may need to periodically or continuously determine their location in the environment in order to perform certain actions. To facilitate this, when placed in an environment that is at least partially unknown to the robotic devices, the robotic devices may acquire visual information about the environment and use that information to construct a map of the environment and to determine their location (i.e., localize the robotic devices in the environment). The robotic devices may then plan to navigate through and perform actions in the environment. In addition to using visual information for performing mapping and localization, robotic devices may also use the visual information for determining changes in a robotic device's position and orientation through a process called visual odometry.
The visual information acquired by the robotic devices may include images of landmarks that are present in the environment and recognizable by the robotic devices. These landmarks may often take the form of unique objects or features that are substantially static in the environment so that the robotic devices may more easily detect the landmarks.